Air filter construction



De@ 29, 1953 c. E. BUTTERFIELD 2,664,172

AIR FILTER CONSTRUCTION Filed June '7, 1951 Fim.

.1NVENTOR.

Patented v Dec. 29, 1953 UNITED sfr-Afrfsrfs regresa* loriucii FILTER CONSTRUCTION "Dharles .f-Butter'field, Newark, -i0hio, :assigner otoLOwens-CorningFiherglascornorationsagcorporationofsDielaware .systems usually consist in .masses of .heteron .geneously .arranged fibers, lfor .-example, rock -wool-.or `glass iibers, .assembled in a relatively thin-.loosely packed, mass,:usually of rectangular y-s'hapewhich are inserted, in theV air passageways of l'heating or air conditioning-systemsfor the .purpose of filtering out `dust which -otherwise would be carried back into the space being heated or conditioned. Because the masses of fibers have to be quite loose, it is necessary that they be bound in some kind of frame or package to hold them together, protect them during manufacture, packaging, shipping, storage and handling and to support them in the passageways.

It is the principal object of this invention to provide a simplied, easily assembled ber retaining means for an air filter which has sufllcient strength not only to hold the fibers in place during use but to form a package during shipment and storage of the filter.

The package constituting the invention comprises two generally flat perforated grills, one to be located on each of the major faces of a mass of loosely packed bers and each of the grills having flanges bent over around the edges of the mass inwardly toward the flanges of the other grill; the whole being made unitary and retained in assembled construction by a single web, preferably formed of a textile tape, which is folded and adhered around the edges of the grill flanges.

An air lter embodying the invention is shown in the attached drawings, in which:

Fig. 1 is a view in perspective of an assembled air filter constructed according to the invention.

Fig. 2 is a greatly enlarged fragmentary, vertical, sectional View taken substantially on the line 2--2 of Fig. 1.

Fig. 3 is a fragmentary perspective view, partly in section, taken substantially along the line 3-3 of Fig. 1.

Fig. 4 is a fragmentary vertical sectional view of a filter construction illustrating a modification of the invention.

An air lter consists in one or more masses of loosely compacted bers I which usually are formed in layers either one or two inches thick and have generally rectilinear shapes. Each of the masses of bers has major, fiat, parallel faces `I.I1"an'd.I2z-over each'nf' which there-'is laid @a `perforated fmetal grill I3 or I4, respectively. In 'the f embodiment of -the i invention shown, the "perforatedmetalrgrills have a plurality of Ycircu- 'lar-openings ithrough .which air passes, leaving structural support for the filter.

In an air-'lter'package or construction accordfingltothe inventionyeachofthe'grills I3 and I4 iszformedwith"inwardly extending ilat flanges I5 or I6 which are'bentpn all fourfsides to form a shallow pan-like structure. In thef'embodb -nient ofthe' invention shown'in the drawings, a "lterfcomprising two "thin wafers of fibers I0 is "shownin'assembled condition. `In making each of these semi-filters the mass of bers IG is laid in the shallow pan-like structure formed by a grill I4 and its bent ilanges I5 or IIB and then the ends of the flanges are bent over to form lips I 'I or I 8 generally parallel to the major planes of the grills I3 or I4.

The two pan-like structures comprising the grills I3 and I4 and the masses of bers I0 are then placed together with the open faces adjacent, the two being assembled particularly as shown in section in Fig. 2. In order to retain the structures in assembled condition and to give the assembled lters unity, a wide fiber reinforced adhesive tape I9 is wrapped around the edges of the two flanges I5 and I6 and its wings are folded over the top and bottom forming a frame around the grills I3 and I4 and retaining the two is assembled condition. The tape I9 may be mitered or lapped at the corners as shown in Fig. 3 and the whole pressed tightly against the material of which the grills I3 and I4 are formed.

Although the grills I3 and I4 are indicated as being made from perforated metal, other ma terials such as thin fiber board or cardboard or other reltively still, tough perforated sheet material. may also satisfactorily be employed.

The embodiment of the invention illustrated in Figs. 1, 2 and 3 consists of two masses of fibers III and their associated grills I3 and I so that the nal finished lter is double thickness. In some applications, single thickness filters may be employed, in which case one of the shallow pan-like structures made up of a grill I3a having flanges I5a is filled with a mass of fibers Illa and a second grill I4a may then either be laid over the open side of the pan shaped structure or it may be formed slightly larger and telescoped over the open side of the pan. Such a construction is illustrated in Fig. 4 Where a grill I4a is shown as having a flange Isa which slides over the exterior of the flange I5a of the grill I3a, the major face of the grill I4@ lying against the exterior of a lip Ha formed on the ange of the grill I3a. As in the embodiment of the invention illustrated in Figs. l, 2 and 3, an adhesive tape I9a which preferably is liber reinforced, is pressed around the edges of the flanges Ia and 16a to retain the two grills I3a and Illa around the mass of fibers Ia.

An air filter construction embodyingr the invention eliminates the necessity for stapling or otherwise mechanically securing the facing grills I3 and I4 or similar elements to each other and the use of flanges formed directly from the same material as that forming the grill faces themselves eliminates the use of expensive framing materials such as are presently employed in most commercial air lters as Well as greatly strengthening the assembled structure.

The particular materials employed for fabricating any of the elements of a grill constructed according to the invention are not critical, it being only necessary that they have suilcient strength and, preferably, light Weight, to retain the ber masses in place during handling and shipping and to hold them generally across the passageway of the air circulating system in which they are employed without greatly interfering with the flow of air or unnecessarily weighting or bulking the completed air filter.

I claim:

1. A lter construction unit consisting of a generally at mat of fibers, said mat having .generally parallel and planar major faces and edges generally perpendicular to such major faces and a retainer for such mat consisting in a thin perforated grill having a flat body overlying one major face of said mat, marginal ilanges extending generally perpendicularly to said body and embracing all of the edges of said mat and return lips extending inwardly over the margins of the other major face of said mat generally parallel to said flat body.

2. An air lter comprising a filter construction unit according to claim 1, a closing cover consisting in a flat, perforated main face and edge flanges perpendicular to said face and arranged in telescoping overlying relation to the flanges of said unit and means for attaching said cover to said unit.

3. An air lter comprising a pair of lter construction units according to claim 1 arranged in back to back relationship with the return lips of each unit in contact and means for securing said units in assembledrelationship.

CHARLES E. BUTTERFIELD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,008,751 Davies July 23, 1935 2,044,221 Myers et al June 16, 1936 2,062,090 Gaarder et al. Nov. 24, 1936 2,108,283 Drew et al. Feb. 15, 1938 2,160,003 Slayter et al May 30, 1939 2,513,946 Kliefoth July 4, 1950 2,569,575 Philipps Oct. 2, 1951 

